I have a VoIP system that interfaces with a TDM-based phone switch (MSL-100) via a Cisco 3845 media gateway. The requirement is that the gateway connect to the MSL-100 using a T1.619a trunk. This is a standard to support MLPP. The trunk works fine currently, but I can't find any documentation stating which interface configurations ( primary-4ess, primary-5ess, primary-dms100, etc.) support this T1.619a standard. Does anyone know where I can find that information?